In February, 1950 the world's largest bomber takes off on a secret Cold War mission from Alaska. Its cargo - a MK IV nuclear bomb. Halfway through the mission three engines catch fire while the bomber is flying near Canada's west coast. Forced to abandon the mission, the crew puts the plane on autopilot, a course that will take the crippled bomber out into the Pacific. Despite the largest search and rescue mission in US Air Force history, the aircraft, five crewmen and their nuclear weapon are presumed lost in the depths of the Pacific Ocean - until now.